Rezumat: Tax investigation is the mean through which tax authorities check how taxpayers fulfil their filling and payment obligations, determining the actual tax situation and identifying the appropriate fiscal treatment on the basis of the verifications carried and the evaluations made. Depending on the manner it is conducted and the taxpayers involved, the tax investigation can take the form of a tax inspection, unannounced check, anti-fraud control, personal tax situation check or documentation check. From these, the present article focuses on the most important aspects regarding the tax inspection.